Interpreting prescription orders is an essential skill in pharmacy practice. Let us start with reading some prescriptions commonly seen in practice. Are you able to accurately interpret all the information on these orders? Write down your responses before viewing the answers at the end of this page.
Prescriptions are not always as legible as the four samples above… I hope you were able to correctly interpret all these orders 😊.
What is covered on this page →
Define prescription orders, drug dose, and dosage form.
Differentiate between the types of prescriptions.
Identify the various parts of a legally written prescription.
Review the abbreviations associated with writing a prescription.
Identify key components of a prescription label.
What is a Prescription?
The definition of a prescription can vary from one country to another. It encompasses various aspects, including the mode of transmission (written vs. electronic), the authorized individuals who can issue a prescription (such as medical doctors, dentists, etc.), and the specific items or medications that different categories of prescribers are legally allowed to prescribe. Below, we provide two definitions that encapsulate what constitutes a prescription. However, it’s important to note that this topic can be quite extensive, exceeding the scope of this page’s intended objective.
What is a Drug?
The definition of the term “drug” can vary depending on the context and the field of study. In general, a drug is a substance that is used to diagnose, treat, cure, mitigate, or prevent disease or to enhance the physical or mental well-being of an individual. Drugs can have various forms, including pharmaceuticals, chemicals, natural compounds, or biological agents.
Drug Generic Name
This name is not owned by a specific commercial entity and can be used by any manufacturer to correctly identify a product containing Acetaminophen as one of the ingredients.
Brand Name
The brand name is a registered proprietary name associated with a product. It is used for marketing and identification purposes. The use of the trademark Tylenol in product labeling is restricted to the registered owner and manufacturer of Tylenol. It’s important to note that in pharmacy practice, the brand name represents the innovator product. Some generic companies may also register a name for their product, in which case it is known as a branded generic. One such example is the brand name for Acetaminophen, which is Panadol, owned by GlaxoSmithKline, or Tylenol, owned by Johnson & Johnson. A branded generic for Acetaminophen is Cetamol, owned by Federated Pharmaceuticals, or Painex, owned by Bioprist Pharmaceuticals.
Dose
The amount of drug to be taken at once to achieve a therapeutic effect or a change in the indicated symptoms. For example, Acetaminophen is used for pain and fever; adults and children 12 years and older should take two tablets (325 mg x 2) per dose to alleviate pain and/or fever.
Understanding Prescription Abbreviations and their Origin
The following pdf document provides a list of common abbreviations used in prescription writing. You may view the document online if you are using a computer to access this page or download the document if you are using a mobile device. You will need a pdf viewer on your mobile device to open the document.
Parts of a Prescription
This recording provides information on the Parts of a Prescription, and the different types of prescriptions.
Components of a Prescription Label and how to Design a Prescription Label
Safe Use of Prescription Abbreviations
The extensive use of Latin abbreviations in prescription writing has become the standard of practice over many years. However, the safe and accurate use of these abbreviations in prescription writing is of paramount importance within the realm of healthcare. Prescription abbreviations, when employed appropriately, can enhance efficiency in communication among healthcare providers and contribute to streamlined patient care. However, it is equally crucial to recognize that the misuse or misinterpretation of abbreviations can have serious consequences, potentially leading to medication errors and adverse patient outcomes. Therefore, a systematic and standardized approach to the use of prescription abbreviations is indispensable to ensure patient safety and the integrity of medical practice. This guide aims to outline the principles and best practices for the safe utilization of abbreviations in prescription writing, emphasizing the critical need for precision and clarity in medical communication.
To avoid ambiguity, use of the following abbreviations is not recommended:
a.u., a.s., a.d. – Latin for both, left and right ears; the “a” can be misread to be an “o” and interpreted to mean both, right or left eyes
bt – intended to mean “bedtime”, but can be misread as “bid” or twice daily.
d/c – can mean “discontinue” or “discharge”. Use “Discontinue” or “Stop” and write out the word “Discharge”.
h.s. – can mean half strength or “hour of sleep” “q.h.s.” and half-strength are preferred.
IJ – intended to mean “injection”, but can be misread as “IV”
IN – intended to mean “intranasal”, but can be misread as “IM” or “IV”
IU – intended to mean “international unit”, but can be misread as “IV” or “10”; instead use “units”.
o.d., o.s., o.u. – the “o” can be misread as “a”. “Od” can mean “once daily” or “right eye”. Instead, use “daily”, “right eye”, and “both eyes”.
OJ – intended to mean “orange juice” but can be misread as “OD” or “OS”
q4PM – intended to mean “at 4 PM”, but can be misread as every 4 hours
q.d., q1d – intended to mean “every day” but can be misread as “q.i.d.” or 4 times a day; instead write “daily”.
q.o.d. – meant “every other day” but the “o” can be interpreted as “.” or “i” resulting in double or eight times the frequency; “alt. die” is preferred or “alternate days”.
SC – meant “subcutaneous” but mistaken for “SL” for “sublingual”
SQ – meant “subcutaneous” but mistaken for “5Q” or 5 every dose; “subcut.” or “subcutaneous” are preferred.
‘ss – intended to mean “sliding scale” or “1/2”, but can be mistaken as “55”
‘SSI, SSRI – intended to mean “sliding scale insulin” or “sliding scale regular insulin”, but can be mistaken as “strong solution of iodine” or “selective serotonin reuptake inhibitor
T.I.W – meant 3 times a week but mistaken for twice a week
U – meant “units” but mistaken for “0”, “4” (so “4U” can become “40” and the “U” is assumed), or misread as “cc” when poorly written; conversely “cc” can be mistaken for “U”, use “units” and for “cc” use “mL”
μg – meant “microgram” but mistaken for “mg”; this 1000-fold error can cause potentially fatal misunderstandings; use “mcg” instead.
Trailing zero- Avoid trailing zero (x.0 mg) the decimal point is often over-looked resulting in 10-fold dosing error.
Lack of leading zero– in the absence of a leading zero (0.x mg) the decimal point is often over-looked resulting in a 10-folding dosing error.
Additional guidance on error-prone abbreviations and safe writing practices is available from the Institute of Safe Medication Practices.
Responses to the Practice Activity at the start of this page
Image #1- Interpretation
Tylenol #3 (30/300)
Sig: 2 tabs PO q6h for pain
# 30
Senokot S
Sig: i PO qHS
# 21
Image #2- Interpretation
Ciprodex eardrops ii for ear bid x 2/52
Nasonex ii for nose od x 1/12
Aerius i PO od x 2/52
Mydocalm 150 mg PO bid x 2/52
Voltaren 50 mg PO tid x 2/52
Image #3- Interpretation
Mobic 15 mg PO od x 2/52
then
Mobic 7.5 mg PO od x 1/12
Pantecta 20 mg PO od x 2/12
Gabapentin 300 mg PO nocte x 2/12
Image #4- Interpretation
PO Apo Famotidine 40 mg nocte x 1/12
PO Sucralfate tab 1 gm BD x 1/12
By: Dwight L. Baker (BPharm, MBA, MPH, Dip.Ed.)
Published: 2023- Sept- 20; Last updated: 2024- Jan- 14